Nine hundred students, initially ages 9 and 10 years, will take part in a controlled clinical trial in which the major objective will be: (1) To identify major cancer and other disease risk factors. (2) To reduce elevated risk status through planned intervention activities. (3) To reinforce and maintain reduced risk status. The major outcome sought will be the primary prevention of cigarette smoking through a peer group approach. In addition nutrition activities will seek to improve nutritional habits and decrease clinical indices of overnutrition. Four program components will provide a motivational sequence of events favoring health-related behavior change. These components are (a) screening, (b) return of screening results to child, (c) curriculum education materials, and (d) anti-smoking and other interventions. Evaluation will be done by comparing smoking onset rates in study versus control schools. In addition, overall risk index scores will be compared as determined from annual re-screening and questionnaires.